5. BIRD RINGING

5.1 Scientific Strategy of the Ringing Scheme

Ringing is an important tool, making a significant contribution to both ecological and conservation-oriented research. It allows the study not only of movements of birds, but also their productivity and survival rates. The scientific strategy of the Scheme is reviewed at approximately 10-yearly intervals to ensure that the BTO Scheme continues to develop and to make the best use of the data collected. The current strategy is based on wide discussions, with invited experts and ringers at a BTO/JNCC workshop, with ringers at a series of workshops held at the annual Ringing & Migration Conference and between the members of a Working Group set up to review the strategy. The Working Group confirmed that the main aim of the BTO Ringing Scheme is to contribute to our understanding of bird population changes by monitoring the productivity, survival rates and dispersal of a wide range of species. A number of projects using ringing were identified as high priority by the Working Group. As part of the strategy ringers are encouraged to take part in those projects for which funding has been obtained and have also been given advice on maximising the value of the data they collect.

Current projects
Constant Effort Sites
Retrapping Adults for Survival
Demographic Analyses for Declining Species of Conservation Concern

Future projects - dependent on funding
Demographic Monitoring of Farmland Birds
Standardised Wader Ringing
Demographic Analyses of Estuarine Wader Populations
Seabird Colour-Mark Programme
Seabird Demography

5.2 Research Using Ring Recoveries

The objectives of ringing-based research are to:

Recent research based on ringing has made a large contribution to IPM (section 2) both through multi-species analyses of survival rates in relation to periods of varying population trends (Siriwardena et al., 1998) and more detailed demographic analyses of individual species, such as the Song Thrush (Thomson et al., 1997 & 1999). IPM analyses involving ringing data are currently underway for a number of other species of conservation concern (Reed Bunting, Linnet, Tree Sparrow and Spotted Flycatcher).

Other recent applied research has investigated the survival rates of Canada Geese and the survival (Wernham & Peach, 1999) and movements of Cormorants in relation to perceived conflicts with inland fisheries. Ring recoveries have been used to estimate the survival rates of Guillemots which have been cleaned and released after oil spills and to compare these with natural survival rates.

Conservation managers and policy-makers require information on bird movements in order to protect the network of sites essential for migrants and for the setting of appropriate hunting regulations, for example. An Atlas of Bird Migration is currently being compiled in order to fulfil many of these information needs and to identify areas in which more detailed work is required. This is a major project that will examine the national and international migration patterns of British and Irish birds. The resulting landmark publication will bring together a massive amount of information generated largely through the Ringing Scheme. Future research on migration will focus on European- or flyway-scale projects.

5.3 Constant Effort Sites and Retrapping Adults for Survival

Constant Effort Sites Ringing Scheme (CES)

The CES scheme uses changes in catch sizes from a network of standardised ringing sites to measure long-term changes in the abundance of adults and juvenile birds, changes in the ratio of adults to young (productivity) and survival rates for a range of common passerines.

CES ringing began in 1981 and around 130 sites are operated each year in Britain and Ireland. Ringers erect mist-nets in the same positions, and for the same length of time, on at least 12 occasions spread evenly between early May and late August. Sites are predominately in scrub (dry and wet) and reedbed habitats, with a small number in deciduous woodland.

Methods have been developed for analysing long-term trends in numbers from CES data (1983-95) for 28 common passerines (Peach et al., 1998). Similar methods have been employed for the analysis of long-term trends in productivity from CES data (1983-98).

Mark-recapture data from CES sites have provided important information on survival rates that have been incorporated into IPM studies. Recent research has investigated the survival rates of Blackbird and Song Thrush.

Retrapping Adults for Survival Ringing Scheme (RAS)

The RAS scheme will use year-to-year retraps of adult birds to monitor adult survival rates of a wide range of species in a wide range of habitats. Particular emphasis will be placed on species of conservation concern and those that are not satisfactorily monitored by other existing schemes. Ringers are asked to retrap a minimum of 20 adults of their chosen species within a defined study area each year and to keep their effort as constant as possible between years. Studies must continue for a minimum of five years. Historical data, collected by ringers in the required manner, can also be submitted within the scheme.

RAS ringing was launched in the 1998 breeding season. More than 130 studies are registered covering more than 45 species. Datasets were received for 75 studies in 1998. Multiple studies of the same species in different habitats and geographical regions are encouraged. This will allow variation in survival rates to be quantified, improving the chances of assessing the environmental causes of any observed demographic changes.

5.4 Administration and Licensing

BTO runs the British and Irish Ringing Scheme, started in 1909. Its broad objectives are:

To this end, BTO:

In recent years developments of the scheme have been geared towards achieving better input to IPM, especially via promotion of CES, see above, and increased computerisation. All recoveries of British-ringed birds are held on computer but only those since 1979 of foreign-ringed birds recovered in Britain. Few of the ringing data (800,000+ birds/year) have been computerised, but ringers are now submitting ringing data on disk. To date (December 1999) details of over half a million ringings have been received and transferred to the HQ database. This total will continue to increase rapidly as the program allowing submission of data on disk is now being used by over 600 ringers.

Key References

Baillie, S.R. (eds) (1996).The scientific strategy of the BTO ringing scheme: report of a working group to the BTO ringing committee. BTO, Thetford.

Baillie, S.R. & McCulloch, M.N. (1993). Modelling the survival rates of passerines ringed during the breeding season from national ringing and recovery data. In: Marked Individuals in the Study of Bird Population (eds. J.-D. Lebreton & P.M. North), pp. 123-139. Birkhäuser, Basel.

Baker, J.K. (1993). Guide to Ageing and Sexing Non-Passerine Birds. BTO, Thetford.

McCulloch, M.N., Tucker, G.M. & Baillie, S.R. (1992). The hunting of migratory birds in Europe: a ringing recovery analysis. Ibis, 134 (Suppl. 1): 55-65.

Peach, W.J. (1993). Combining mark-recapture data sets for small passerines. In: Marked Individuals in the Study of Bird Populations (ed. J.-D. Lebreton & P.M. North), pp. 107-122. Birkhäuser, Basel.

Peach, W.J., Baillie, S.R. & Balmer, D.E. (1998). Long-term changes in the abundance of small passerines in Britain and Ireland as measured by Constant Effort mist-netting. Bird Study, 45: 257-275.

Peach, W.J., Baillie, S.R. & Underhill, L. (1991). Survival of British Sedge Warblers Acrocephalus schoenobaenus in relation to west African rainfall. Ibis, 133: 300-305.

Peach, W.J., Buckland, S.T. & Baillie, S.R. (1996). The use of constant effort mist-netting to measure between year changes in abundance and productivity of common passerines. Bird Study, 43(2): 142-157.

Peach, W.J., Thompson, P.S. & Coulson, J.C. (1994). Annual and long-term variation in the survival rates of British Lapwings Vanellus vanellus. Journal of Animal Ecology, 63: 60-70.

Siriwardena, G.M., Baillie, S.R. & Wilson, J.D. (1998). Variation in the survival rates of some British passerines with respect to their population trends on farmland. Bird Study, 45: 276-292.

Siriwardena, G.M., Baillie, S.R. & Wilson, J.D. (1999). Temporal variation in the annual survival rates of six granivorous birds with contrasting population trends. Ibis, 141: 621-636.

Spencer, R. (1984). The Ringer's Manual. 3rd edition. BTO, Tring.

Thomson, D.L., Baillie, S.R. & Peach, W.J. (1997). The demography and age-specific annual survival of song thrushes during periods of population stability and decline. Journal of Animal Ecology, 66: 414-424.

Thomson, D.L., Baillie, S.R. & Peach, W.J. (1999). A method for studying post-fledging survival rates from ringing recoveries. Bird Study, 46: S104-111.

Toms, M.P., Clark, J.A. & Balmer, D.E. (1999). Bird Ringing in Britain and Ireland in 1997. Ringing & Migration, 19: 215-255.

Wernham, C.V. & Peach, W.J. (1999). The use of ring recoveries to monitor long-term changes in the survival rates of British and Irish Cormorants Phalacrocorax carbo. Bird Study, 46, S189-197.

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